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Cards In This Set
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What are the pH ranges for arterial and venous blood?
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Arterial: 7.35-7.45
Venous: 7.31-7.41 |
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Abnormal H+ concentrrations can result in:
Changing the shape and reducing the function of hormones and enzymes Changing the distribution of otherr electrolytes, causing fluid and electrolyte imbalances Changing excitable membranes, making the heart, nerves, muscles, and GI tract either less or more active than normal decreasing the effectiveness of many drugs |
The major acid of the body is carbonic acid (H2CO3) and the major base of the body is bicarbonate (HCO3-). The body keeps a ratio of 20:1 of bicarbonate to carbonic acid.
The carbonic anhydrase equation is important CO2 + H2O = H2CO3 = H+ + HCO3- (the = means double arrows) When more CO2 is present then more carbonic acid forms which forms more H+, likewise when more H+ is present more CO2 forms. CO2 and H+ are directly related to one another. pH can also be described as pH = kidneys (bicarbonate)/Lungs (carbon dioxide) |
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Protein breakdown causes what by product?
Fat breakdown forms what? Incomplete breakdown of glucose forms what? |
Protein = sulfuric acid
Fat = fatty acids and ketones Glucose = lactic acid Side note, the kidneys reabsorb bicarb but the pancrease produces it. |
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Normal ranges:
PaO2 = ? PaCO2 = ? bicarb = ? |
Pa02 = 80-100
PaCO2 = 35-45 bicarb = 21-28 pH below 6.9 and above 7.8 is fatal usually for all of theses values the venous is higher except for pH which is a little lower. |
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Homeostasis depends on:
Hydrogen ion prod. is consistent and not excessive CO2 loss from the body through breathing keeps pace with hydrogen ion production The ratio b/w carbonic acid and bicarbonate remains 20:1 |
Dd
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What is the first line of defense against pH changes?
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Buffers, respiratory is second, and renal is third
Protein buffers are the most common, the 2 most common protein buffers are albumin and glubulins (i.e. hemoglobin) |
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Check the serum potassium level for any pt who has acidosis, also asses heart rate and rhythm for any pt with an acid base imbalance
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Renal Acid-base control, 3 ways:
Kidney movement of bicarbonate - (1st), by kidney movement of bicarb made elsewhere and second by kidney prod. of bicarb, if acidic pull bicarb from urine Formation of acids - urine has an excess of phosphate (HPO42-) sadf which pulls in H+ and binds it Formation of ammonium - NH3 from protein breakdown binds H+ in urine formin ammonium NH4+ which traps the H+ |
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Renal compensation is more powerful than respiratory but renal usually takes several hours to be triggered
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Acidoses is not a disease but it is a condition caused by a disorder or pathologic process. older adults with health problems and people with respiratory problems are at a greater risk of acidosis
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What is the difference b/w actual acid excess and relative acidosis?
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Actual is acidosis caused by overproducing acids, relative is when the amount or strength of bases decreases - this is caused by overeliminating bases or underprodcing bases
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Changes in H+ ions causes changes in other positively and negatively charged ions especially K+ which can disrupt nerves, cardiac muscle and skeletal muscle
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Older Adults:
Can pt complete a sentence w/o stopping to take a breath Examine skin turgor over sternum and on forehead |
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Metabolic acidosis can occur from 4 things:
Overproduction of hydrogen ions Underelimination of hydrogen ions Underproduction of bicarbonate ions Overelimination of bicarbonate ions |
Overproduction of hydrogen ions: fatty acid breakdown, anaerobic breakdown of glucose, excessive intake of acids including alcohol.
Respiratory Acidosis can occur from 4 things: Respiratory depression Inadequate chest expansion Airway obstruction Reduced alveolar-capillary diffusion |
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Taking a history:
Older pt more at risk, ask about breathing problems, kidney failure, diabetes mellitus, diarrhea, pancreatitis, and fever Obtain a nutritional report including carbs, protein, and fat |
Clinical manifestations:
CNS - depression of CNS function, lethargy, confussion, stupor, coma Neuromuscular - reduced muscle tone and deep tendon reflexes (hyperkalemia along with acidosis) Cardiovascular - increased HR and CO at first, if if worsens then decreased HR, tall T wave and wide QRS complex Respiratory - kussmauls respirations (breaths are deep and rapid and not under control) Skin- warm, flushed, dry skin in metabolic acidosis, pale to cyanotic skin in respiratory acidosis Psychosocial - behavioral changes may be the first manifestations of acidosis - document this by objective description rather than subjective (interpretation) i.e. dont say pt is confused, rather write pt does not recognize close family members |
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How is hyperkalemia formed from acidosis?
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H+ enters cells, in order to keep the balance K+ leaves cells causing hyperkalemia
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Nursing diagnoses related to acidosis:
Deficient fluid volume r/t dehydration Decrease CO r/t poor cardiac contractility and decreased vascular V Risk for falls r/t skeletal muscle weakness Impaired memory r/t fluid and electrolyte imbalances Ineffective breathing pattern r/t reduced gas exchange Fatigue r/t inadequate tissue oxygenation |
Interventions for acidosis - interventions seek to fix the underlying problem.
Metabolic acidosis: hydration (if a result from dehydration), administration of bicarb IF bicarb levels are low, insulin if it is diabetic ketoacidosis Respiratory acidosis: maintain a patent airway, Rx like broncho dilators, anti-inflammatories, amd mucolytics to increase diameter of airways and to thin pulmonary secretions, repositioning pt, increase fluids to thin secretions, ventialation for pt's below O2 sat of 90, |
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What is the difference b/w actual and relative alkalosis?
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Actual alkolosis is an anctual base excess from over production or underelimination. Relative alkalosis is when the amount or strength of bases does not increase, but rather the amount or strength of acids decreases (overelimination or underproduction of acids).
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